CONGRATULATIONS to all the award winners at Top Gun this year, and especially to our jet-flying buddies. The success of the Scale-jet competitors this year was unbelievable, with first places in Expert Scale, Designer Scale, Team Scale, and the Top Gun award winner. I'll leave it to the Top Gun articles to bring you the details, but I am sure this success will be a topic throughout the Scale community. The neat thing for those of us who attend jet fun-flys across the country is how often we see these same modelers, and their Scale jets, flying at the meets. All those who attended Superman 2001 can think back to how many of the Top Gun Scale competition models were in attendance, and in most cases flying, and you realize that these guys didn't compete with hangar queens, but with well-tested, well-flown Scale aircraft. Expert Scale winner Joe Rafalowski flew a Jet Model Products T-33 designed and manufactured by Tom Cook. This is an older design, but it is still one of the highest-quality, most sophisticated fully molded airframe kits on the market today. The complete package, including landing gear, wheels and brakes, fuel systems, and the turbine-installation package, is well proven for use in competition and sport flying. The new Bob Violett Models F-100 flown by Bob Violett in Designer Scale and by the team of Joe Grice and David Shulman in Team Scale is a newer entry to the market, but one that is proving to be reliable and durable. Let's be honest; Tom Cook and Bob Violett know that a majority of their customers want these Scale models for sport flying and very few will ever see the pressure of competition. The demands placed on sport models are far greater than those placed on a Scale model; reliable, durable systems are required. A sport model's success is measured by the maintenance hours per flight—not the judge's score. Please don't misunderstand me and think that only these two manufacturers provide quality products; many others are equal, but the T-33 and the E-100 have just had an opportunity to showcase themselves in the hands of some incredibly talented modelers at a special event. We are fortunate as modelers to have so many products of such high quality that a good-flying, reliable, enjoyable aircraft can also be a Scale model. This is true not only of jet-model kits, but of those of military and civilian propeller-model kits available today. You may say that the skills of these award-winning modelers are beyond those of mere mortal modelers, but I say that's not the case. You just have to learn some of the techniques that make these people exceptional craftsmen. One thing I have always admired at the jet meets is how some people can achieve those perfect fits to their hatches. How do they do it? A few years ago I learned the secret, and it's not hard; it just takes time to perfect. The fit of hatches on even the highest-quality kits is a reflection of the limitations of the molding process. Most modelers expect the hatch to fit into place with minimal cleanup of the mold lines. What you have is a hatch that fits into place, but the gap and fit have been compromised to assure this functional fit. The gap can be made tighter, and the fit can be made more accurate, but it takes a few additional steps. Once you have the hatch in place with all mounting brackets installed, it is time to work on the fit and the gap. Start by creating sharp, crisp edges to the hatch corners. Do this by building up additional material on the hatch comer. I prefer to use a mix of epoxy and a product called Cabosil. or microballoons. Cabosil is available from many sources that supply composite materials, including those within the hobby industry. This product is basically a lightweight filler intended to increase the viscosity of an epoxy mix. The resulting mix, when cured, is easily sanded and requires no filling. Start the process by creating a dam to hold the epoxy/Cabosil mix in place. I use clear-plastic packaging tape attached to the hatch's fuselage mating surface to create my dam. The epoxy mix will not adhere to the plastic packaging tape, allowing easy removal of the tape. Add the mix to the outside corner of the hatch—only in the corner. Once dry, sand the epoxy/Cabosil mix flush with the outer, finished surface of the hatch skin. Sand the corners of the hatch following the curvature of the fuselage skin to create accurate, sharp edges on the hatch. Do all your sanding on the model with a sanding block, and never sand without a backing block; freehand sanding creates wavy surfaces. There are many excellent sanding blocks available, or a simple 1 '/* x I x 12-inch wood block can make an excellent sanding block. Contact-cement 100-grit sandpaper on one side and 150-grit sandpaper on the other side. This block will allow you to create accurate, straight surfaces and corners. Now the hatch has clean, crisp edges, so next you work on the fuselage's mating surface. Apply plastic packaging tape to the hatch surfaces that mate to the fuselage. This time the front face will serve as the release side. Trial-fit the hatch to assure a good fit with no interference from the tape. Once ready, start the filling process. My preference at this stage is to use a lightweight, sandable automotive body filler. Be careful in your selection; use the lightweight, sandable product—not regular automotive body filler. You may have to go to an automotive paint store to find this product; many automotive-parts shops only carry the heavier body fillers. With the hatch removed, apply a bead of the lightweight body filler to the fuselage surface that mates to the hatch. Install the hatch, making sure that the body filler only makes contact with hatch surfaces protected by the packaging tape. This is critical for release of the hatch once the filler cures. The lightweight body filler should push out beyond the fuselage surface for removal later with the sanding block. Once the lightweight body filler is cured, use the sanding block to shape the filler to make a perfect fit between the hatch and the fuselage surfaces. Again, don't hand sand without a sanding block; you are creating a perfect, smooth surface (lowing from the fuselage skin to the hatch skin. Additional body filler may be required to fill any voids left after sanding. Continue this process until no voids or surface imperfections remain. Remove the hatch with the tape acting as your release surface. Pull off the tape and refit the hatch. When done correctly, you will be rewarded with that perfectly filled gap. with a smooth, almost seamless fit between the hatch and the fuselage. This process can be used anywhere on the model to create perfect fits and gaps. Wing butt joints and even gear-door fits can be tightened with this method. That lightweight automotive body filler will find many other uses in achieving the perfect look, be it on wing fillets, in dent filling, or in building up a surface where the lines don't quite match. A slight variation on this theme is well presented in the article 'Toward Seamless" by Steven Ellzey on the Jet Pilot's Organization Web site under Tips and Techniques. Should you pursue the art of building the perfect model, read this article at www.jetpilots.orgV A question I often hear when a modeler is converting ducted-fan models to turbine, or even when building some of the turbine kits available today, is, Where can I purchase fuel tanks for Jet-A in my new model? Unless you're building a completely packaged turbine kit, fuel tanks are left up to the modeler. The options range from large, plastic model fuel tanks all the way up to composite, custom tanks. Planes Plus is one source with a line of Kevlar™ composite tanks in a variety of shapes for our needs. Some of these tanks were created for models such as the Kangaroo, which is a FiberClassics kit also sold by Planes Plus. This is a good starting point if you're in search of the right tank. Check out Planes Plus at www.planesplus.com or call (630) 904-5075. Through the years I have learned that many of the special tanks created for sport jet models lend themselves well to fitting into other models as well. The use of quality fuel tanks is important to the success of your turbine model. The most common cause of a flameout is an air bubble in the fuel system. Use great care in this area. Most manufacturers strongly suggest a good header tank installed in the fuel system to reduce the chance of an air bubble. Till next time, may your turbine never release that puff of smoke in the sky. Been there, done that—hate those air bubbles.
Edition: Model Aviation - 2002/10
Page Numbers: 110, 111
Edition: Model Aviation - 2002/10
Page Numbers: 110, 111
CONGRATULATIONS to all the award winners at Top Gun this year, and especially to our jet-flying buddies. The success of the Scale-jet competitors this year was unbelievable, with first places in Expert Scale, Designer Scale, Team Scale, and the Top Gun award winner. I'll leave it to the Top Gun articles to bring you the details, but I am sure this success will be a topic throughout the Scale community. The neat thing for those of us who attend jet fun-flys across the country is how often we see these same modelers, and their Scale jets, flying at the meets. All those who attended Superman 2001 can think back to how many of the Top Gun Scale competition models were in attendance, and in most cases flying, and you realize that these guys didn't compete with hangar queens, but with well-tested, well-flown Scale aircraft. Expert Scale winner Joe Rafalowski flew a Jet Model Products T-33 designed and manufactured by Tom Cook. This is an older design, but it is still one of the highest-quality, most sophisticated fully molded airframe kits on the market today. The complete package, including landing gear, wheels and brakes, fuel systems, and the turbine-installation package, is well proven for use in competition and sport flying. The new Bob Violett Models F-100 flown by Bob Violett in Designer Scale and by the team of Joe Grice and David Shulman in Team Scale is a newer entry to the market, but one that is proving to be reliable and durable. Let's be honest; Tom Cook and Bob Violett know that a majority of their customers want these Scale models for sport flying and very few will ever see the pressure of competition. The demands placed on sport models are far greater than those placed on a Scale model; reliable, durable systems are required. A sport model's success is measured by the maintenance hours per flight—not the judge's score. Please don't misunderstand me and think that only these two manufacturers provide quality products; many others are equal, but the T-33 and the E-100 have just had an opportunity to showcase themselves in the hands of some incredibly talented modelers at a special event. We are fortunate as modelers to have so many products of such high quality that a good-flying, reliable, enjoyable aircraft can also be a Scale model. This is true not only of jet-model kits, but of those of military and civilian propeller-model kits available today. You may say that the skills of these award-winning modelers are beyond those of mere mortal modelers, but I say that's not the case. You just have to learn some of the techniques that make these people exceptional craftsmen. One thing I have always admired at the jet meets is how some people can achieve those perfect fits to their hatches. How do they do it? A few years ago I learned the secret, and it's not hard; it just takes time to perfect. The fit of hatches on even the highest-quality kits is a reflection of the limitations of the molding process. Most modelers expect the hatch to fit into place with minimal cleanup of the mold lines. What you have is a hatch that fits into place, but the gap and fit have been compromised to assure this functional fit. The gap can be made tighter, and the fit can be made more accurate, but it takes a few additional steps. Once you have the hatch in place with all mounting brackets installed, it is time to work on the fit and the gap. Start by creating sharp, crisp edges to the hatch corners. Do this by building up additional material on the hatch comer. I prefer to use a mix of epoxy and a product called Cabosil. or microballoons. Cabosil is available from many sources that supply composite materials, including those within the hobby industry. This product is basically a lightweight filler intended to increase the viscosity of an epoxy mix. The resulting mix, when cured, is easily sanded and requires no filling. Start the process by creating a dam to hold the epoxy/Cabosil mix in place. I use clear-plastic packaging tape attached to the hatch's fuselage mating surface to create my dam. The epoxy mix will not adhere to the plastic packaging tape, allowing easy removal of the tape. Add the mix to the outside corner of the hatch—only in the corner. Once dry, sand the epoxy/Cabosil mix flush with the outer, finished surface of the hatch skin. Sand the corners of the hatch following the curvature of the fuselage skin to create accurate, sharp edges on the hatch. Do all your sanding on the model with a sanding block, and never sand without a backing block; freehand sanding creates wavy surfaces. There are many excellent sanding blocks available, or a simple 1 '/* x I x 12-inch wood block can make an excellent sanding block. Contact-cement 100-grit sandpaper on one side and 150-grit sandpaper on the other side. This block will allow you to create accurate, straight surfaces and corners. Now the hatch has clean, crisp edges, so next you work on the fuselage's mating surface. Apply plastic packaging tape to the hatch surfaces that mate to the fuselage. This time the front face will serve as the release side. Trial-fit the hatch to assure a good fit with no interference from the tape. Once ready, start the filling process. My preference at this stage is to use a lightweight, sandable automotive body filler. Be careful in your selection; use the lightweight, sandable product—not regular automotive body filler. You may have to go to an automotive paint store to find this product; many automotive-parts shops only carry the heavier body fillers. With the hatch removed, apply a bead of the lightweight body filler to the fuselage surface that mates to the hatch. Install the hatch, making sure that the body filler only makes contact with hatch surfaces protected by the packaging tape. This is critical for release of the hatch once the filler cures. The lightweight body filler should push out beyond the fuselage surface for removal later with the sanding block. Once the lightweight body filler is cured, use the sanding block to shape the filler to make a perfect fit between the hatch and the fuselage surfaces. Again, don't hand sand without a sanding block; you are creating a perfect, smooth surface (lowing from the fuselage skin to the hatch skin. Additional body filler may be required to fill any voids left after sanding. Continue this process until no voids or surface imperfections remain. Remove the hatch with the tape acting as your release surface. Pull off the tape and refit the hatch. When done correctly, you will be rewarded with that perfectly filled gap. with a smooth, almost seamless fit between the hatch and the fuselage. This process can be used anywhere on the model to create perfect fits and gaps. Wing butt joints and even gear-door fits can be tightened with this method. That lightweight automotive body filler will find many other uses in achieving the perfect look, be it on wing fillets, in dent filling, or in building up a surface where the lines don't quite match. A slight variation on this theme is well presented in the article 'Toward Seamless" by Steven Ellzey on the Jet Pilot's Organization Web site under Tips and Techniques. Should you pursue the art of building the perfect model, read this article at www.jetpilots.orgV A question I often hear when a modeler is converting ducted-fan models to turbine, or even when building some of the turbine kits available today, is, Where can I purchase fuel tanks for Jet-A in my new model? Unless you're building a completely packaged turbine kit, fuel tanks are left up to the modeler. The options range from large, plastic model fuel tanks all the way up to composite, custom tanks. Planes Plus is one source with a line of Kevlar™ composite tanks in a variety of shapes for our needs. Some of these tanks were created for models such as the Kangaroo, which is a FiberClassics kit also sold by Planes Plus. This is a good starting point if you're in search of the right tank. Check out Planes Plus at www.planesplus.com or call (630) 904-5075. Through the years I have learned that many of the special tanks created for sport jet models lend themselves well to fitting into other models as well. The use of quality fuel tanks is important to the success of your turbine model. The most common cause of a flameout is an air bubble in the fuel system. Use great care in this area. Most manufacturers strongly suggest a good header tank installed in the fuel system to reduce the chance of an air bubble. Till next time, may your turbine never release that puff of smoke in the sky. Been there, done that—hate those air bubbles.
